The present invention relates to a slide unit for use in a sliding closure unit for controlling the discharge of molten metal from a metallurgical vessel. The present invention further relates to a partial plate member of such a slide unit.
More particularly, the present invention relates to such a slide unit and partial plate member thereof wherein the slide unit includes two partial movable refractory plates having respective planar sealing surfaces and mounted together in a frame to be movable together with the sealing surfaces thereof sliding against a stationary refractory plate of a sliding closure unit, with each of the partial plates being surrounded circumferentially by a band, for example a metal band such as a sheet metal band.
The partial plates, each of which can be replaced individually, include, for example, a pouring plate having therethrough a discharge opening and a closing plate. However, it is also possible to provide two adjacent partial pouring plates which are used alternatively. It is necessary to surround each partial plate with a metal jacket or band, which can be formed as a tension band or as a component of a metal shell with a bottom area, in order to hold each respective partial plate together if cracks occur in the refractory material thereof during use.
A slide unit of the above type is disclosed in DE-OS No. 21 46 677, wherein the two partial movable refractory plates abut against one another at their circumferential bands, and edges of both bands are exposed at the top of the thus assembled plates. This arrangement can disturb the close fit of the sealing surfaces with the stationary refractory plate of the sliding closure unit during operation as a result of differing heat expansions of the refractory material of the plates and the material of the bands. Furthermore, when the plates are moved to a position such that the edges of the bands are beneath the discharge opening of the stationary refractory plate, the molten metal therein makes contact with the bands. This can result in damage to the sealing surfaces of the plates during further operation due to hardened steel which adheres to the bands, or can make more difficult a replacement of one of the partial plates due to the occurrence of a "welding together" of the edges of the abutting bands.